How to Get AHCI Working Properly in Server 2008 with Hyper-V
ASUS M3A78-EM MotherboardAMD Athlon 64 X2 Dual Core Processor 6000+(Yes -- Hyper-V does work with the above combination.)There are five SATA drives installed in the system. Three are internal and two are in 5 /14 exposed bays that let them be easily swap.When I originally installed Server 2008 with Hyper-V I had the SATA chip set to SATA. Unfortunately, Server 2008 does not see the SATA drives as removable -- they do not show up in the Safely Remove Hardware window. (I have a similar setup with XP and all of the SATA drives on that system show up in the Safely Remove Hardware window.)In researching the problem it appeared that I had to change the setting of the SATA chip to AHCI. Of course that presents a problem as the boot drive is one of the SATA drives. There is a knowledgebase article that explained that if you enabled the Msahci.sys driver in the registry you could change the SATA mode from SATA to ACHI and be able to boot the system. This worked. However, the SATA drives still do not show up in Safely Remove Hardware. I also noticed that they now show up as SCSI drives in Device Manager whereas before they were listed as SATA drives. Furthermore, when I list the Driver File Details the two files that are shown are disk.sys and partmgr.sys -- both from Microsoft. The msahci.sys file is not listed.There are two knowledgebase articles that refer to problems with SATA drives: KB960635 and KB961078. Article ID: 960735 - Last Review: January 13, 2009 - Revision: 2.0 When you access a SATA device that supports the Native Command Queuing (NCQ) feature in Windows Vista or in Windows Server 2008, you may experience poor performanceArticle ID: 961078 - Last Review: January 19, 2009 - Revision: 1.0 Safe removal functionality is unavailable for an eSATA device that is connected to a computer that is running Windows Vista SP1 or Windows Server 2008 Both of them include replacements for msahci.sys -- neither has replacements for disk.sys or partmgr.sys. The first one has a date of 15-Dec-2008 and the second one is 18-Dec-2008. However, if the msahci.sys driver is not currently being used I don't think replacing it will help much.Why do the SATA drives showup in Device Manager as SCSI drivers.Should msahci.sys show up as one of the driver files for the SATA drives. If it should how do I force it?KB961078 talks about eSATA drives. My drives are not technically eSATA but they should still be removable. Feedback on KB961078 and the hotfix associated with it from anyone that has applied it would be appreciated.
April 24th, 2009 6:19am

Hi Saberman, According to the description, the issue seems not related to Hyper-V. Hyper-V is only a component of Windows Server 2008(the version with Hyper-V build-in), you should encountered this "problem" also with Windows Server 2008 without Hyper-V version. There are some different sayings with SATA and AHCI and I suspect you may have a misunderstanding of SATA and AHCI. Generally speaking, a motherboard support with SATA will have several Mode for SATA hard disk. One mode is AHCI, one is IDE or Compatibility or ATA, and there maybe another RAID if it support RAID. If you select AHCI, the SATA hard disk will work at AHCI mode, if you select IDE (or Compatibility or ATA), the SATA hard disk will work at IDE mode. See the different modes in different BIOSs: For more information, you can refer to: Any Difference in Running HDD in SATA or IDE? http://www.tomshardware.com/forum/245263-32-difference-running-sata The SATA hard disk show as a removable disk in the system, its a little defects for Nvidia chipset driver. It said they resolve this defects in the latest chipset driver. For more information, you can refer to: Hot Swappable SATA HDD's? http://forums.nvidia.com/lofiversion/index.php?t25792.html In addition, I recommend that you initial a post in Nvdias forum or some hardware forum for more information. Thanks for your understanding. Important Note: This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites; therefore, Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software from the Internet. Best regards, Vincent Hu
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April 24th, 2009 10:11am

I'm ata very similar step as saberman in changing my Windows Server Enterprise 2008 R2 originally installed with my SATA setting at "IDE Emulation(?)" to "AHCI". I'm amazed more articles and manuals with Install sections wouldn't point this out since it's somewhat hidden, and new technology where just a year or two ago anyone would just assume an enabled SATA didn't need further attention to work right. saberman said: In researching the problem it appeared that I had to change the setting of the SATA chip to AHCI. Of course that presents a problem as the boot drive is one of the SATA drives. There is a knowledgebase article that explained that if you enabled the Msahci.sys driver in the registry you could change the SATA mode from SATA to ACHI and be able to boot the system. This worked. When I changed my BIOS setting to AHCI today I suddenly couldn't boot up, and I found the article to which I believe he's referring. The article I read is KB922976 and this worked for me, even though it only actually addresses Vista and 7.Of course, the similarity to saberman's situation and mine ends there, because my boot disk is my only disk. I'm just on an evaluation copy tinkering at home.I just wanted to give anyone finding this article in a search for "ahci" an easier way to possibly solve their problem. I'm not trying to one-up saberman in any way. I'm sure the omision of the link was to reduce confusion, especially because of the server OS's omision from the KB's APPLIES TO section.I hope this was helpful.
September 17th, 2009 8:42am

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